The immunomodulatory properties of C-Med 100 an extract of the plant Uncaria tomentosa

Abstract: Extracts from the bark of the vine Uncaria tomentosa have anti-inflammatory, antiviral, antimutagenic and antioxidant effects. In this study, we evaluate the effects of an Uncaria tomentosa extract, denoted C-Med 100, on the cellular level of the immune system both in vivo and in vitro. Our results indicated that lymphocytes had significantly prolonged half life after in vivo supplementation with C-Med 100. This phenomenon significantly increased the number of all leukocyte subsets in the spleen without influencing proliferation capability or cell cycle progression after in vitro stimulation. Fractionation of the extract identified quinic acid (QA) as a possible active component and supplementation with QA significantly increased the number of spleen cells, recapitulating the in vivo effect of C-Med 100. Furthermore the in vitro studies revealed that NF-kB activity was significantly inhibited in both C-Med 100 and QA treated cells, providing an explanation for the reported anti-inflammatory effects of Uncaria tomentosa extracts. C-Med 100 also inhibited the proliferation of normal mouse T and B lymphocytes as well as various tumour cell lines. The inhibition was not caused by toxicity or by induction of apoptosis and no discrete cell cycle block was observed. In contrast, QA did not interfere with cell proliferation, suggesting that inhibition of proliferation and NF-kB activity were independent events. Collectively our study has identified QA as a candidate constituent of the C-Med 100 extract inducing increased cell numbers in vivo and inhibiting NF-kB activity in vitro.